Many technologies have been devised for devices that project video for display.
PATENT LITERATURE 1 discloses the following technique: “It is an object to provide a hand and finger gesture detection device capable of detecting a state of a hand and a finger quickly at low cost. The hand and finger gesture detection device includes a plurality of light sources, a camera, and an image recognition unit. The plurality of light sources emit light from plural positions to the hand and finger that is entered onto a detection surface, thus forming a plurality of shadow images of the hand and finger onto the detection surface, with each shadow corresponding to individual irradiating light. The camera is disposed at a position vertically away from the detection surface to pick up the plurality of shadow images and hand and finger images formed by the plurality of light sources. The image recognition unit recognizes the plurality of shadow images and hand and finger images picked up by the camera, and detects the state of the hand and finger entered onto the detection surface according to the state of the shadow images and the hand and finger images (excerpt from abstract)”.
PATENT LITERATURE 2 discloses the following technique: “It is an object to provide an information display device that easily determines a hand and finger of a user used for operation. A display control device controls display content of a display device in accordance with the movement of a hand of the user. The display control device includes an identification unit that identifies the hand of the user as a hand for operation when the hand of the user is recognized as being directed in the same direction as the face of the user, in accordance with a detection result of a detection sensor that detects a spatial position of the body of the user, an instruction acquiring unit that recognizes the movement of the hand for operation and acquires an operating instruction for the display content of the display device, and a display control unit that controls the display content of the display device in accordance with the operating instruction (excerpt from abstract)”.
PATENT LITERATURE 3 discloses the following technique: “It is an object to provide an operation display device which can accurately determine whether touch operations simultaneously detected at a plurality of points are a multi-touch operation by one operator or individual single touch operations by a plurality of operators. When a plurality of touch operations on a display screen are simultaneously detected, the operation display device determines whether the plurality of touch operations are carried out by one operator or a plurality of operators on the basis of finger forms (e.g., similarity between areas or forms of contact parts, or consistency/inconsistency of directions of fingertips) related to individual touch operations detected by a finger form detection unit, and changes display content of the display unit in accordance with the result of determination (excerpt from abstract)”.
PATENT LITERATURE 4 discloses the following technique: “It is an object to enable input by discriminating a command based on movement of an object such as a hand of a user and a command based on a gesture of the object other than the movement. An input user interface device includes an electronic camera which picks up an image including an object image, a shape detection unit which detects a shape of the object image in the image picked up by the electronic camera, a gesture detection unit which detects a gesture of the object image in the image picked up by the electronic camera, and a control unit which decides a command on the basis of the shape detected by the shape detection unit and the gesture detected by the gesture detection unit (excerpt from abstract)”.